Parc Hydro-Quebec

In Montreal’s Quartier des Spectacles, an interesting little park is tucked between two buildings, designed by renowned landscape architect, Claude Cormier. It features a raised metal grill of varying widths that functions as a pedestrian walkway/court, punctuated with Honeylocust trees and star-shaped benches. Native perennials and ground covers are planted in the low-lying areas along the sides of the park. The walkway, essentially one large tree grate, protects the underlying soil from compaction and allows for rainwater infiltration, promoting healthier trees and sustainable stormwater management. In fact, there are no impervious surfaces in this park that are larger than the benches. Appropriately, the park is situated next to the green-roofed Centre for Sustainable Development.

Parc Hydro-Quebec 1
Parc Hydro-Quebec with the Centre for Sustainable Development in the background

Parc Hydro-Quebec 2

Parc Hydro-Quebec 3
Interesting use of pottery shards instead of gravel beneath the walkway

Parc Hydro-Quebec 4

Photos by Alice Webb

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A Sustainable Campus Quad

During a recent trip to Salem, Massachusetts, I visited a well-designed quadrangle within a new residence hall complex at Salem State University. A linear bioswale runs along one side of a large lawn area, collecting runoff from the complex, and cleaning this water before it enters a tidal marsh adjacent to the development. Stepped stone-filled gabions line the walkway along the swale, and are intermittently capped with wooden bench seating. Wooden ramps bridge the swale from the walkway, providing access to the lawn area. I think the juxtaposition of the linear architectural elements and the free-form planting design of the swale work well. Even in winter (unusually without snow on this visit), the grasses and other plantings provide visual interest.
 

Bioswale with adjacent gabions
 

Wooden bench seating caps portions of the gabions. A green roof sits atop the single-story dining hall (in background).
 

A row of ornamental grasses visually reinforces yet softens the line of this concrete wall, and attractive pavers complement the building colors.
 

Plantings along this building remain colorful in winter.

Photos by Alice Webb

Tanner Springs Park – A Lesson in History and Sustainability



Tanner Springs Park, in the Pearl District of Portland, Oregon, is a unique example of ecological sustainability within an urban area. It was built on a former industrial site, and a natural habitat was created to represent the historic ecosystem that existed in this part of the Willamette River valley prior to development of the city.

The site slopes down from west to east, and the western end is planted with trees to portray an Oak savannah prairie. A native grassland was planted downhill from the savannah, sloping down into a wetland, and ultimately to a pond at the east end of the park.

All rain water that falls within the park boundaries is cleansed and recycled on site. Water seeps into the soil, migrates to a subgrade cistern, and is then treated by an ultraviolet light system, also located under ground. The clean water then emerges as a “spring” in the grassland, and flows through a meandering runnel into the pond.

Some materials installed in the park also represent the industrial past of the city. Belgian blocks that pave some of the walkways were originally used as ballast on ships that navigated the Columbia River, and later used as surfacing for Portland’s streets. Also, an art installation at the east end of the park consists of a wavering wall of vertical rail tracks, interspersed with blue stained glass panels displaying images of insects – a merging of man-made and natural references. The rail tracks are relics of 19th century Portland.


A “spring” emerges from the ground in the prairie zone.


Water flows from the “spring” through a winding runnel.


Cobbled walkways transition to stone dust surfacing in the grassland zone.


A pond is situated at the east end of the park.


View to the west: pond in foreground, followed by wetland, native grassland, and Oak savannah prairie zones


Shelter, boardwalk, & rail track wall


Back (street) side of rail track wall

Photos by Alice Webb

RiverEast Center: A Sustainable Site


 
An example of a successful public-private partnership involving sustainable stormwater management is RiverEast Center in Portland, Oregon. The site includes numerous vegetated infiltration swales that filter and cleanse runoff from the parking lot, walkways, building roof, and adjacent public street. The swales were constructed at a gentle gradient to allow the water to readily soak into the soil, rather than be rapidly carried off to storm drains. Plantings, mulch, and stones cover all the unpaved surfaces; no high-maintenance turfgrass can be found on the property. The site also includes several recycled concrete slabs, set on edge, that serve as sculptural and functional elements. The office building is a renovated warehouse (with a new façade) that has achieved LEED gold certification from the U.S. Green Building Council.
 

A vegetated infiltration swale is situated between a pedestrian walkway and the parking area. This walkway connects to a bicycle/pedestrian path along the Willamette River.
 

This infiltration swale is located between parking bays. A raised storm drain at the end of each swale takes in excess stormwater during heavy rain events.
 

Roof water from a building scupper is slowed by a gravel bed (edged with recycled concrete slabs) and is then directed through a slot in the taller slab to a vegetated infiltration bed on the left side of this photo.
 

During heavy rain storms, roof runoff that can’t entirely soak through the plant bed next to the building is conveyed through this walkway channel into an infiltration swale.
 

Stormwater from the adjoining public street is directed through several walkway channels into the adjacent infiltration swale on the RiverEast Center property.
 
Photos by Alice Webb

Green Streets of Portland, Oregon

Portland, Oregon, is known as one of the greenest cities in the U.S., receiving high marks for public transportation, bicycle/carpool commuting, renewable energy usage, recycling, and number of LEED-certified buildings. It also has quite a few innovative environmentally-sustainable sites, including several “green streets”. These streetscapes incorporate special planters that decelerate runoff and filter pollutants from the water before it reaches the storm pipe system.

During a recent visit to Portland, I had the opportunity to see a couple of these green street projects in the downtown area: one on Southwest 12th Avenue within Portland State University, and another on Southwest Park Avenue across from Director Park. There are several other green streets scattered around the city, and many of these have their own unique design.

The 12th Avenue site was the first of its kind, built in 2005. In addition to its stormwater management function, it has enhanced the visual quality of the existing streetscape. In this case, stormwater flows into the first of four planters, and settles into the soil. During heavy storms, if the water level in this planter reaches more than 6 inches, the excess amount will flow back out into the gutter and then flow into the next planter for infiltration, repeating the process. Water exceeding 6 inches height in the last (lowest) planter will flow out to the street and enter the storm drain system. The number of planters functioning in this manner depends on the intensity and duration of each rain event. The planters are filled with a native species called Grooved Rush (Juncus patens), and each also includes a Black Gum tree (Nyssa sylvatica). Both of these species tolerate saturated soil conditions. In addition, a 3’-wide strip of pavers is located along the street side, providing space for access to parked cars. Pedestrian walkways are also situated between the planters, bounded by small shrubs.


The Southwest 12th Avenue planters include a strip of pavers for parked vehicle access.


Excess runoff from the lowest planter enters the storm drain system.


The planters and vegetation fit nicely into the urban streetscape.


Each street-side planter inlet includes a small hump in the asphalt to direct water into the planter.

The planters on Park Avenue are designed in a different manner. The largest planter (pictured below) is divided into three sections. Water enters the planters from drain inlets along the street side, and from gaps in the curbing along the sidewalk. When water in the highest planter section exceeds the height of the divider during large rain events, that runoff will flow over the divider into the next section. Most of the water will filter into the soil in the planters, but during the heaviest storms it may reach the third (lowest) planter section. If the water level in this section reaches the height of the elevated drain inlet located within it, this excess water will enter the inlet and flow into the storm pipe system.


Southwest Park Avenue planter with drain inlets connecting to each divided section


Raised drain inlet within the lowest planter section


Gaps in curbing along the sidewalk receive runoff.


One of several individual tree planters along Southwest Park Avenue only receives runoff from the walkway side. A small raised drain in the planter takes in excess water during heavy storms.

Photos by Alice Webb